Editor’s note: The Focus on Research column highlights different research projects being conducted at Penn State. Each column features the work of a different researcher from across all disciplines.
At Penn State’s Center for Innovative Materials Processing through Direct Digital Deposition (CIMP-3D), a graduate student watched closely as an open-source 3-D printer created a tiny blue polymer component, layer by layer. In four minutes or so, the component would be fully formed.
“The open architecture of this type of 3-D printer is perfect for materials development testing,” said Tim Simpson, professor of mechanical and industrial engineering and co-director of CIMP-3D. “It gives you the ability to change things — how fast it runs, how hot it runs. You can even print components for building another printer.”
A few rooms over, Simpson gestures to another machine — this one much larger.
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“Here we can print metal components up to 30 inches by 20 inches by 20 inches,” he said. “The vacuum chamber is so large, you can stand inside it. We had to take the windows off the building to get it in.”
The two machines illustrate the range of capabilities of the CIMP-3D lab. The center — a partnership among Penn State’s Applied Research Laboratory, the College of Engineering and the College of Earth and Mineral Sciences — is equipped to support research on all facets of 3-D printing, or additive manufacturing.
“This facility gives us an ideal opportunity to bring together all the expertise, the equipment, the capabilities,” Simpson said.
CIMP-3D is a hub of activity that accommodates students, faculty and industry partners. Because the center specializes in 3-D printing of metals such as steel, nickel and titanium, much of the work focuses on building real components (rather than models and prototypes). Through computer simulations, scientists can understand processes and material interactions within a particular machine then use that knowledge to determine the best materials and processes for printing a component for an aerospace company or a medical device manufacturer.
Unlike 3-D printing with polymers, in which the polymer is heated and squeezed out glue-gun style, 3-D printing with metals typically starts with metallic powder. The powder is melted with a laser or an electron beam, and then it gets built up layer by layer into a 3-D shape. Although some of the metal components printed are used as conceptual models, the majority of the work in CIMP-3D involves printing real components meant to be used in an airplane, on a vehicle or even an artificial hip joint.
“When you think about the uses of these parts, you realize that it’s critical that they function properly,” Simpson said. “It has to look right, fit right, feel right and, most importantly, work right.”
The largest machine at the center — the one that necessitated removing windows — is a $2.5 million 3-D printer on consignment from Sciaky Inc.
“Using this machine is like welding on steroids,” Simpson said. “An electron beam melts metal wire, such as titanium, at the rate of 15 to 20 pounds per hour, at temperatures of thousands of degrees, so we’re learning about how different structures and shapes react under different heating and cooling rates.”
Another machine acts as a CT scanner for metals, producing detailed, layer-by-layer images of 3-D-printed parts. This allows researchers to see the internal geometry of parts and then adjust the design or additive manufacturing process. For example, small holes in a gas turbine blade are critical for cooling and efficiency. Being able to view the internal structure of the cooling passages allows researchers to spot any defects or problems and validate intricate new geometries.
“With this technology, we are challenging basic assumptions — for example, why are holes round?” Simpson said. “For years, traditional manufacturing methods dictated the internal features that we could fabricate, but that’s no longer the case with additive manufacturing.”
Collaboration with industry has resulted in many fruitful partnerships for CIMP-3D.
“We looked at many potential partners for our research in additive manufacturing,” said David Rowatt, research director of mechanical and materials sciences at Schlumberger.
“We chose Penn State based on the CIMP-3-D facility and the breadth and depth of the research in additive manufacturing being done there,” he said. “In particular, we were impressed by Penn State’s multi-disciplinary approach to additive manufacturing, including aspects of mechanics, materials science and manufacturing. The Penn State team has a solid understanding of the key issues surrounding the adoption of additive manufacturing in industry, and it shows in how they approach their work and the results it yields.”
The research and partnerships emerging from CIMP-3D are just the beginning, Simpson said, noting that additive manufacturing technology offers nothing less than a reinvigoration of the manufacturing industry and new opportunities for design.
“The capability to produce complex products and consolidate parts quickly is unprecedented,” he said. “It’s changing the economics of the game, and the possibilities are almost endless.”